1. Field of the Invention
The present invention relates generally to processing human blood products, i.e., whole blood, red blood cells, blood plasma and blood proteins. Additionally, it relates to processing human and animal tissue, e.g., organs and parts of organs used in transplants. More particularly, this invention relates to disinfecting certain blood products and corneas so that they may be used safely and effectively for diagnostic, therapeutic or research purposes.
2. Description of the Related Art
Blood products from human and animal donors are widely used for therapeutic, diagnostic and experimental purposes. Such blood products are subject to contamination by several blood-borne viruses and other micro-organisms. There has been no way to assure that the recipients of blood products or those who handle the products are free from potential exposure to viruses. In particular, the transfusion of human blood products carries a well-known risk of transmitting a number of viruses.
Of particular threat are viruses that appear to cause various forms of hepatitis, including the hepatitis B virus; the non-A, non-B hepatitis virus or viruses. Others of interest are cytomegalovirus and Epstein-Barr virus.
Viruses linked with the incurable and often fatal disease known as acquired immune deficiency syndrome or "AIDS" are probably caused by a retrovirus or group of retroviruses previously denominated "HTLV-III" and other HTLV types--and more currently "HIV," "HIV-1," "HIV-2," "HIV-3" AND "HIV-4." The most common cause of AIDS is thought to be HTLV-III, now usually called HIV-1.
Detection and isolation of such cytopathic retroviruses from patients with AIDS, and certain members of groups that are at high risk for AIDS, have been frequently reported. One such report appears in Science 224:500-03 (1984).
Such findings are corroborated by P. S. Savin, et al. in an article entitled "Human T-Lymphotrophic Retroviruses in Adult T-cell Leukemia-Lymphoma and Acquired Immune Deficiency Syndrome," J. Clinical Immunol. 4:415-23 (1984). Yet another report is by F. Wong-Staal and R. C. Gallo, "Human T-Lymphotrophic Retroviruses," Nature 317:395-402 (1985).
While the hazard of hepatitis and AIDS transmission through transfusion of blood products has received great public attention, the analogous hazard of such transmission through transplantation tissues is a much less familiar matter. Nevertheless, there is a recognized possibility of at least AIDS virus transmission from corneal transplantation, according to Corneal Surgery Theory, Technique and Tissue, F. S. Brightbill, ed., p. 53 (Mosby 1986).
Furthermore, contamination of corneas by bacteria and fungi is documented, id. at 52, even though antibacterial solutions are commonly used in pre-transplant storage of corneas--generally within the nutrient medium that supports the corneas.
Disinfecting blood products and tissue products with disinfectants strong enough to significantly inactivate viruses has generally been discounted because they damage cellular blood constituents, and any residual desinfectant in the blood product to be transfused could be hazardous to the recipient of the transfusion.
One disinfectant in use for blood products is beta-propiolactone. In this field, it is usually employed to disinfect plasma preliminary to fractionation. Such a process has been used for isolation of therapeutic immune globulin, Factor VIII and IX, and other blood proteins. Beta-propiolactone, however, is a known carcinogen and hence potentially very dangerous. To the extent that significant residual quantities of this material may remain in the blood product which is actually transfused, the use of propiolactone represents a significant hazard.
U.S. Pat. No. 4,833,165 relates to using as little as 0.1% formaldehyde and/or phenol to inactivate HTLV-III in blood. However, recently available data and information indicate that red blood cells treated with as little as 0.02% formaldehyde and 0.01% phenol are not viable and not suitable for transfusion.
A variety of disinfectants have been used in the medical profession and biomedical industry to disinfect work areas, table tops, walls, surgical instruments, etc., for the purpose of inactivating viruses and micro-organisms associated with blood and tissue products. In particular, U.S. Pat. No. Re. 31,779 relates to the effective use of materials which liberate chlorine dioxide for such purposes. Other compositions which are known in the medical profession to be useful for sterilizing and disinfecting work areas and tools are lower alkyl monohydric alcohols, aldehydes, mineral acids and bases, peroxides, sodium hypochlorite, quaternary ammonium salts and iodine containing compounds. None of these disinfectants have been applied to disinfecting blood products or tissue products. Such compositions in contact with blood and tissue products would cause one to expect resulting damage to the cells and tissue.
Accordingly, there presently is a need to provide a method to disinfect human and animal blood products and human and animal tissue products. In particular, there is a need to disinfect such products so that they can be safely and effectively utilized by a recipient or handled by a user without exposure to harmful viruses and microorganisms.